Neutrinos slower than light, but continue to befuddle physicists

A recent experiment has demonstrated that neutrinos do not, in fact, travel faster than light. But this ethereal subatomic particle continues to undermine established physical models in other ways.

By
Trevor Quirk /
March 16, 2012

In this image, technicians install the detector at the Sudbury Neutrino Observatory in Ontario, Canada. In 2001, the detector gave physicists the first direct evidence that the spectral neutrino had mass.

When scientists at the European Organization for Nuclear Research (CERN) last year apparently measured neutrinos traveling faster than light, physicists were largely skeptical. Their skepticism now seems justified, as another recent CERN experiment has contradicted the measurements.

Ever since Einstein published the special theory of relativity in 1905, an immutable speed of light has been an integral part of the framework of theoretical physics. Scientists – including the team that measured the superluminal neutrinos – were never willing to discard Einstein's crucial idea after just one experimental result.